"You would expect people to make more accurate decisions when given the time to look properly."

The researchers said that in their test, the instinctive decisions were more likely to be correct because the subconscious brain recognised a rotated version of the same object as different from the original, whereas the conscious brain could identify the two objects as identical, albeit in different orientations.

Dr Li said: "The conscious or top-level function of the brain, when active, vetoes our initial subconscious decision - even when it is correct - leaving us unaware or distrustful of our instincts and at an immediate disadvantage.

"Falling back on our inbuilt, involuntary subconscious processes for certain tasks is actually more effective than using our higher-level cognitive functions."

Advantage

Kim Stephenson, a psychologist researching some aspects of decision-making, said subconscious reactions could be an advantage in some situations.

He said people and animals were designed subconsciously to recognise and fixate on anything out of the ordinary as it could help to identify and escape from predators quickly, and so has an evolutionary advantage.

He said: "Your subconscious mind is more useful for specific things, where you don't have time and need to react quickly.

"It's not to say that if you've got to make a decision you should make it in a fraction of a second - that is daft.

"But your body is designed to do some things very quickly, so using instincts would be better there."

Dr Li agreed: "The trick is knowing when this applicable or not. Trusting your instincts is only useful in some situations."

Other research has drawn similar conclusions. Malcolm Gladwell published a best-selling book on the topic last year called Blink.